Build ROOT Ntuple from other source. This program reads the `aptuple.txt' file row by row, then creates the Ntuple by adding row by row.
Author: Wim Lavrijsen
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Thursday, January 20, 2022 at 11:38 PM.
import sys, os from ROOT import TFile, TNtuple, TROOT ifn = os.path.join(str(TROOT.GetTutorialDir()), 'pyroot', 'aptuple.txt') ofn = 'aptuple.root' print('opening file %s ...' % ifn) infile = open( ifn, 'r' ) lines = infile.readlines() title = lines labels = lines.split() print('writing file %s ...' % ofn) outfile = TFile( ofn, 'RECREATE', 'ROOT file with an NTuple' ) ntuple = TNtuple( 'ntuple', title, ':'.join( labels ) ) for line in lines[2:]: words = line.split() row = map( float, words ) ntuple.Fill(*row) outfile.Write() print('done')